First generation (1G) wireless communications began in the late 1970's and featured early cellular mobile radio telephone systems using analog voice signaling. Second generation (2G) wireless communications began in the early 1990's and featured digital voice encoding, such as Global System for Mobile (GSM) service and Code Division Multiple Access (CDMA).
Advances in the state of wireless technology and capability from second generation to the current 2.5G wireless communications are associated with General Packet Radio Services (GPRS). The 1G, 2G, and 2.5G wireless communications lack the bandwidth to provide digital multimedia information, such as video information. In particular, present data capabilities have very low bit rates (e.g., 10 kilobits per second) allocated to each user. With such a low bit rate, streaming multimedia information (i.e., audio and video) is not realistic. For example, MP3 requires at least 64 kilobits per second, while video requires at least a few hundred kilobits per second.
UMTS (Universal Mobile Telecommunications Service) (i.e., “third-generation (3G)),” provides broadband, packet-based transmission of text, digitized voice, video, and multimedia at data rates up to 2 megabits per second (Mbps), and offers a consistent set of services to mobile computer and phone users no matter where they are located in the world. However, a problem arises in that only a single user within a cell of a tower may receive the information at the 2 megabits per second rate.
Furthermore, when the user is moving away from the tower, reception of the signal may fade. In order to compensate for the fading effects, the technology is designed to increase reception of the signal. Increasing signal reception is typically achieved by reducing the data rate to the mobile device, such that as the user gets further away from the cell tower, the data rate incrementally decreases from 2 megabits per second, down to, illustratively, 64 kilobits per second or 32 kilobits per second, depending on the distance from the tower. As such, the current system does not support multimedia information being sent contemporaneously to multiple users.
A problem associated with cellular systems is that of interference from adjacent cells. The interference problem exists for all 3G cellular systems that use code division multiplexing to separate users within a cell. If a user is between two adjacent towers, (i.e., the fringe area) the mobile device has to tune to one of the channels, while tuning out (i.e., filtering) the other channel. Typically, interference arises from adjacent channels at the fringe areas between adjacent towers, because the cell towers transmit at various power levels. That is, the closer the user is to the tower, the less power is required, while the further away from a tower (e.g., the fringe area) the more power is required. Consequently, the bit rate achievable at the fringe and is lower than the middle of the cell, which creates inconsistent services for the users.
As such, there is a need to provide multimedia services to multiple users of mobile cellular devices. Furthermore, there is a need to provide consistent multimedia services to such users regardless of the user's location within a cell.